Latin

Adverb

efficāciter ‎(comparable efficācius, superlative efficācissimē)

1. efficaciously, effectually

References

• efficaciter in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• efficaciter in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• Félix Gaffiot (1934), “efficaciter”, in Dictionnaire Illustré Latin-Français, Paris: Hachette.